1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device having a nitride-based semiconductor field effect transistor structure and a method for manufacturing the same.
2. Description of the Related Art
Generally, a group III-nitride-based semiconductor including group III elements such as gallium (Ga), aluminum (Al), indium (In), or the like, and nitrogen (N), has characteristics such as wide energy band gap, high electron mobility, saturation electron speed, and high thermochemical stability, and the like.
A nitride-based field effect transistor (N-FET) based on the group III-nitride-based semiconductor is manufactured using a semiconductor material having a wide energy band gap, for example, gallium nitride (GaN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), aluminum indium gallium nitride (AlINGaN), or the like.
The semiconductor device of the general nitride-based field effect transistor includes abase substrate, a nitride-based semiconductor layer formed on the base substrate, and a source electrode and a drain electrode formed on the semiconductor layer, and a gate electrode formed on the semiconductor layer between the source electrode and the drain electrode.
However, the field effect transistor using gallium nitride (GaN) is continually in a ‘turned-on’ state in which current flows due to low resistance between the drain electrode and the source electrode when gate voltage is OV (normal state), such that it consumes current and power. Therefore, in turning-off the field effect transistor, there is a disadvantage in that negative voltage should be applied to the gate electrode (normally-on structure).